Fix test_tx_change_edge

Author: jirijakes

lightning/src/util/transaction_utils.rs

@@ -226,30 +226,29 @@ mod tests {
 	#[test]
 	fn test_tx_change_edge() {
 		// Check that we never add dust outputs
-		let mut tx = Transaction { version: 2, lock_time: LockTime::ZERO, input: Vec::new(), output: Vec::new() };
+		let mut tx = Transaction { version: Version::TWO, lock_time: LockTime::ZERO, input: Vec::new(), output: Vec::new() };
 		let orig_wtxid = tx.wtxid();
 		let output_spk = ScriptBuf::new_p2pkh(&PubkeyHash::hash(&[0; 0]));
 		assert_eq!(output_spk.dust_value().to_sat(), 546);
-		// 9 sats isn't enough to pay fee on a dummy transaction...
-		assert_eq!(tx.weight().to_wu(), 40); // ie 10 vbytes
-		assert!(maybe_add_change_output(&mut tx, 9, 0, 250, output_spk.clone()).is_err());
+		assert_eq!(tx.weight().to_wu(), 42); // 3 * (base size = 4 + 1 + 1 + 4 = 10) + (total size = 4 + 2 + 1 + 1 + 4 = 12)
+		// 10 sats isn't enough to pay fee on a dummy transaction...
+		assert!(maybe_add_change_output(&mut tx, Amount::from_sat(10), 0, 250, output_spk.clone()).is_err());
 		assert_eq!(tx.wtxid(), orig_wtxid); // Failure doesn't change the transaction
-		// but 10-564 is, just not enough to add a change output...
-		assert!(maybe_add_change_output(&mut tx, 10, 0, 250, output_spk.clone()).is_ok());
+		// but 11 (= ceil(42 * 250 / 1000)) is, just not enough to add a change output...
+		assert!(maybe_add_change_output(&mut tx, Amount::from_sat(11), 0, 250, output_spk.clone()).is_ok());
 		assert_eq!(tx.output.len(), 0);
 		assert_eq!(tx.wtxid(), orig_wtxid); // If we don't add an output, we don't change the transaction
-		assert!(maybe_add_change_output(&mut tx, 549, 0, 250, output_spk.clone()).is_ok());
+		assert!(maybe_add_change_output(&mut tx, Amount::from_sat(549), 0, 250, output_spk.clone()).is_ok());
 		assert_eq!(tx.output.len(), 0);
 		assert_eq!(tx.wtxid(), orig_wtxid); // If we don't add an output, we don't change the transaction
-		// 590 is also not enough, if we anticipate 2 more weight units pushing us up to the next vbyte
-		// (considering the two bytes for segwit flags)
-		assert!(maybe_add_change_output(&mut tx, 590, 2, 250, output_spk.clone()).is_ok());
+		// 590 is also not enough
+		assert!(maybe_add_change_output(&mut tx, Amount::from_sat(590), 0, 250, output_spk.clone()).is_ok());
 		assert_eq!(tx.output.len(), 0);
 		assert_eq!(tx.wtxid(), orig_wtxid); // If we don't add an output, we don't change the transaction
-		// at 590 we can afford the change output at the dust limit (546)
-		assert!(maybe_add_change_output(&mut tx, 590, 0, 250, output_spk.clone()).is_ok());
+		// at 591 we can afford the change output at the dust limit (546)
+		assert!(maybe_add_change_output(&mut tx, Amount::from_sat(591), 0, 250, output_spk.clone()).is_ok());
 		assert_eq!(tx.output.len(), 1);
-		assert_eq!(tx.output[0].value, 546);
+		assert_eq!(tx.output[0].value.to_sat(), 546);
 		assert_eq!(tx.output[0].script_pubkey, output_spk);
 		assert_eq!(tx.weight().to_wu() / 4, 590-546); // New weight is exactly the fee we wanted.